1. Field of the Invention
The present invention relates to a window covering, and more particularly, to a manually-controlled or motorized roller shade system having light-redirecting features. More particularly, this invention relates to roller window shade systems employing light directing sheets with embedded reflective surfaces.
2. Description of Background Art
Roller shades used to control the amount of sunlight entering a space and to provide privacy are usually mounted in front of windows or openings in building facades and employ flexible shade fabric wound onto an elongated roller tube for raising and lowering the shade fabric by rotating the roller tube. In a typical roller shade, the fabric is either opaque or translucent which limits light control to blocking or admitting light by lowering and raising the shade. However, many applications exist where it is desired that the roller coverings could redirect light instead of blocking. For example, daylight intercepted by a roller shade can be harvested and used for illumination by redirecting it to the ceiling of a building interior, thus saving electric energy. Redirecting excess light to the ceiling can also reduce the intensity of the direct beam propagating in the downward direction thus reducing glare and improving comfort for building occupants.